车载光电系统电视摄像机光学系统设计及杂散光分析

Optical system design and stray light analysis on TV camera of vehicle electro-optical system

  • 摘要: 设计了一款双视场电视摄像机,小视场用于对目标的跟踪,大视场用于捕获和观察目标,两视场光学系统的传递函数MTF在50 lp/mm频率处均大于0.6,点列斑直径均小于像元尺寸5.5 μm,畸变均小于0.1%。两视场共用一个面阵CCD成像器件,通过分光棱镜分光。由于在该光学系统中分光棱镜表面反射会产生杂散光,形成鬼像。因此,利用LightTools软件对系统进行了杂散光的仿真分析。分析结果表明:大视场的半视场角在5.7°~7.6°之间和小视场的半视场角在2.6°~3.5°之间的入射光线被分光棱镜下表面反射后,以及小视场的半视场角在-2.7°~-3.5°之间的入射光线被分光棱镜后表面反射后, 变成杂散光,聚焦到像面, 形成鬼像,采用在分光棱镜后方设置消杂光光栏的方法来抑制杂散光。验证结果表明,仿真分析准确,提出的消杂光措施有效。

     

    Abstract: A dual-field TV camera was designed, which can realize target tracking in narrow field,and target capturing and observing in wide field. Both of the transfer modulation functions(MTFs) of the optical systems of the two field of views(FOVs) are more than 0.6 at 50 lp/mm frequency, the spot diameters are both smaller than the pixel size of 5.5 μm, and the distortions are less than 0.1%. The two FOVs share a common planar array CCD imaging device. And the light can be split through a prism. Considerting the ghost images due to the stray lights generated by the reflecting on the prism surfaces,the LightTools software was utilized to simulate and analyze the stray lights . The simulation indicates that when the half angle of field is between 5.7°~7.6° in wide field, and 2.6°~3.5° in narrow field,the incidences can be reflected by the down surface of the prism; when the half angle of field is between -2.7°~-3.5° in narrow field,the incidences can be reflected by the back surface of the prism. Then they can be focused on the image surface to form the ghost images and stray lights. The method of eliminating stray light in the rear of the split prism is adopted to suppress stray light. The simulation results show that the simulation analysis is correct,and the resolution proposed to suppress the stray lights can be proved to be valid.

     

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